The present invention relates generally to agricultural machinery and, more particularly, to improvements to combine harvesters for agricultural crops.
Combine harvesters have a cutting mechanism, a threshing mechanism and a conveying channel for transferring crop material from the cutting mechanism to the threshing mechanism. Various designs for combine harvester conveying channels are known. Conveying channels are generally obliquely arranged channel housings which are pivotally connected to the machine frame of a combine harvester. Revolving conveying chains and conveying bars are connected to the machine and convey the crop material in an undershot manner to the threshing device, as described in German Patent 3 406 696 2. The conveying chains are entrained over sprockets which are fixed to the upper drive shaft and which simultaneously deflect the chains. A disadvantage of this design is that in the region of these sprockets, and particularly on their side flanks, crop material accumulates and jams between the moving and stationary components. This occurs particularly in the case of moist crop material and causes the conveying chains to be lifted off the teeth of the sprockets during harvesting operation. Consequently, the conveying chains skip, causing skewing and the uncertainty of synchronous running of the individual chain runs with each other. Also stress arises within the conveying chain, which may cause it to break and damage the machine, resulting in machine failure.
It is an object of the invention to provide a design for the conveying chains that avoids the accumulation of crop material in the region of upper deflection (i.e. the upper rear terminus of the conveying chains), allowing for more trouble free operation of the harvesting machine.